If you haven't played HeroClix in 5 years, be advised the game has drastically changed since it's original version. It's changed VERY much, and I think, for the worse. It used to be a pretty simple game, but now there's cards and everything else that can be used...

But to answer your question, no, I don't know. I never did any tournaments myself. Was always just a game we played among friends. I would imagine, however, as long as they're actual, official HeroClix pieces (and not customs), that you should be able to use them?